///////////////////////////////////////////////////////////////////////////////////
/// OpenGL Mathematics (glm.g-truc.net)
///
/// Copyright (c) 2005 - 2015 G-Truc Creation (www.g-truc.net)
/// Permission is hereby granted, free of charge, to any person obtaining a copy
/// of this software and associated documentation files (the "Software"), to deal
/// in the Software without restriction, including without limitation the rights
/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
/// copies of the Software, and to permit persons to whom the Software is
/// furnished to do so, subject to the following conditions:
/// 
/// The above copyright notice and this permission notice shall be included in
/// all copies or substantial portions of the Software.
/// 
/// Restrictions:
///		By making use of the Software for military purposes, you choose to make
///		a Bunny unhappy.
/// 
/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
/// THE SOFTWARE.
///
/// @ref core
/// @file glm/detail/func_geometric.inl
/// @date 2008-08-03 / 2011-06-15
/// @author Christophe Riccio
///////////////////////////////////////////////////////////////////////////////////

#include "func_exponential.hpp"
#include "func_common.hpp"
#include "type_vec2.hpp"
#include "type_vec4.hpp"
#include "type_float.hpp"

namespace glm {
    namespace detail {
        template<template<class, precision> class vecType, typename T, precision P>
        struct compute_dot {
        };

        template<typename T, precision P>
        struct compute_dot<tvec1, T, P> {
            GLM_FUNC_QUALIFIER static T call(tvec1<T, P> const &a, tvec1<T, P> const &b) {
                return a.x * b.x;
            }
        };

        template<typename T, precision P>
        struct compute_dot<tvec2, T, P> {
            GLM_FUNC_QUALIFIER static T call(tvec2<T, P> const &x, tvec2<T, P> const &y) {
                tvec2<T, P> tmp(x * y);
                return tmp.x + tmp.y;
            }
        };

        template<typename T, precision P>
        struct compute_dot<tvec3, T, P> {
            GLM_FUNC_QUALIFIER static T call(tvec3<T, P> const &x, tvec3<T, P> const &y) {
                tvec3<T, P> tmp(x * y);
                return tmp.x + tmp.y + tmp.z;
            }
        };

        template<typename T, precision P>
        struct compute_dot<tvec4, T, P> {
            GLM_FUNC_QUALIFIER static T call(tvec4<T, P> const &x, tvec4<T, P> const &y) {
                tvec4<T, P> tmp(x * y);
                return (tmp.x + tmp.y) + (tmp.z + tmp.w);
            }
        };
    }//namespace detail

    // length
    template<typename genType>
    GLM_FUNC_QUALIFIER genType length(genType x) {
        GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559,
                          "'length' only accept floating-point inputs");

        return abs(x);
    }

    template<typename T, precision P, template<typename, precision> class vecType>
    GLM_FUNC_QUALIFIER T length(vecType<T, P> const &v) {
        GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559,
                          "'length' only accept floating-point inputs");

        return sqrt(dot(v, v));
    }

    // distance
    template<typename genType>
    GLM_FUNC_QUALIFIER genType distance(genType const &p0, genType const &p1) {
        GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559,
                          "'distance' only accept floating-point inputs");

        return length(p1 - p0);
    }

    template<typename T, precision P, template<typename, precision> class vecType>
    GLM_FUNC_QUALIFIER T distance(vecType<T, P> const &p0, vecType<T, P> const &p1) {
        return length(p1 - p0);
    }

    // dot
    template<typename T>
    GLM_FUNC_QUALIFIER T dot(T x, T y) {
        GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559,
                          "'dot' only accept floating-point inputs");
        return x * y;
    }

    template<typename T, precision P, template<typename, precision> class vecType>
    GLM_FUNC_QUALIFIER T dot(vecType<T, P> const &x, vecType<T, P> const &y) {
        GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559,
                          "'dot' only accept floating-point inputs");
        return detail::compute_dot<vecType, T, P>::call(x, y);
    }

    // cross
    template<typename T, precision P>
    GLM_FUNC_QUALIFIER tvec3<T, P> cross(tvec3<T, P> const &x, tvec3<T, P> const &y) {
        GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559,
                          "'cross' only accept floating-point inputs");

        return tvec3<T, P>(
                x.y * y.z - y.y * x.z,
                x.z * y.x - y.z * x.x,
                x.x * y.y - y.x * x.y);
    }

    // normalize
    template<typename genType>
    GLM_FUNC_QUALIFIER genType normalize(genType const &x) {
        GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559,
                          "'normalize' only accept floating-point inputs");

        return x < genType(0) ? genType(-1) : genType(1);
    }

    template<typename T, precision P, template<typename, precision> class vecType>
    GLM_FUNC_QUALIFIER vecType<T, P> normalize(vecType<T, P> const &x) {
        GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559,
                          "'normalize' only accept floating-point inputs");

        return x * inversesqrt(dot(x, x));
    }

    // faceforward
    template<typename genType>
    GLM_FUNC_QUALIFIER genType
    faceforward(genType const &N, genType const &I, genType const &Nref) {
        return dot(Nref, I) < static_cast<genType>(0) ? N : -N;
    }

    template<typename T, precision P, template<typename, precision> class vecType>
    GLM_FUNC_QUALIFIER vecType<T, P>
    faceforward(vecType<T, P> const &N, vecType<T, P> const &I, vecType<T, P> const &Nref) {
        return dot(Nref, I) < static_cast<T>(0) ? N : -N;
    }

    // reflect
    template<typename genType>
    GLM_FUNC_QUALIFIER genType reflect(genType const &I, genType const &N) {
        return I - N * dot(N, I) * static_cast<genType>(2);
    }

    // refract
    template<typename genType>
    GLM_FUNC_QUALIFIER genType refract(genType const &I, genType const &N, genType const &eta) {
        GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559,
                          "'refract' only accept floating-point inputs");

        genType const dotValue(dot(N, I));
        genType const k(static_cast<genType>(1) -
                        eta * eta * (static_cast<genType>(1) - dotValue * dotValue));
        return (eta * I - (eta * dotValue + sqrt(k)) * N) *
               static_cast<genType>(k >= static_cast<genType>(0));
    }

    template<typename T, precision P, template<typename, precision> class vecType>
    GLM_FUNC_QUALIFIER vecType<T, P>
    refract(vecType<T, P> const &I, vecType<T, P> const &N, T eta) {
        GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559,
                          "'refract' only accept floating-point inputs");

        T const dotValue(dot(N, I));
        T const k(static_cast<T>(1) - eta * eta * (static_cast<T>(1) - dotValue * dotValue));
        return (eta * I - (eta * dotValue + std::sqrt(k)) * N) *
               static_cast<T>(k >= static_cast<T>(0));
    }
}//namespace glm
